Childhood obesity as a risk factor for lateral condyle fractures over supracondylar humerus fractures

Abstract

Background: Obese children reportedly have an increased risk of sustaining musculoskeletal injuries compared with their normal-weight peers. Obese children are at greater risk for sustaining fractures of the forearm, particularly from low-energy mechanisms. Furthermore, obesity is a risk factor for sustaining an extremity fracture requiring surgery. However, it is unclear what role obesity plays in fractures about the distal humerus.

Questions/purposes: We therefore asked whether (1) children who sustain lateral condyle (LC) fractures have a higher body mass index (BMI) as compared with those with supracondylar (SC) humerus fractures; and (2) children with a higher BMI sustain more severe fractures regardless of fracture pattern.

Methods: We retrospectively reviewed 992 patients: 230 with LC injuries and 762 with SC fractures. We determined BMI and BMI-for-age percentiles. Fracture types were classified by the systems proposed by Weiss et al. (LC fractures) and Wilkins (SC fractures).

Results: The LC group had both a higher mean BMI and BMI-for-age percentile than the SC group as well as had more obese patients (37% versus 19%). Within the LC group, children with Type 3 fractures had a higher BMI that those with Type 1 fractures (19 versus 17). There was a higher percentage of obese patients with Type 3 LC fractures compared with Type 1 and 2 fractures (44% versus 27% and 26%). Among patients with SC fractures, there was no difference among the BMI, BMI-for-age percentiles, or percentage of obese children when analyzed by fracture subtype.

Conclusions: Obesity places a child at greater risk for sustaining a LC fracture and when these fractures occur, they are often more severe injuries compared with those in nonobese children.

Level of evidence: Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Fig. 1

The illustration shows how patients were selected. fxs = fractures.

Fig. 2A–B

Proposed mechanisms of lateral condyle fractures versus supracondylar fractures. (A) Lateral condyle fracture: obese child sustaining a low-velocity injury as a result of a fall from a standing height. As a result of their increased weight status, the obese child is unable to fully extend their arm to get their center of mass over their outstretched arm. This results in a varus moment about the elbow resulting in a lateral condyle fracture. (B) Supracondylar humerus fracture: normal-weight child sustaining a higher velocity injury resulting from a fall from a height. This child sustained a supracondylar humerus fracture as a result of their ability to get their center of mass over their fully extended outstretched arm most commonly resulting in an extension-type elbow injury.